Recently, air pressure sensors has started to be implemented on mobile device, such as cell phones. The air pressure sensor is used to measure air pressure; and the growing popularity of the sensor may be considered to have increased as the usage rate increases in the mobile industry.
There are some barometers (such as plum bob type barometer, liquid silver type barometer) used as standard reference equipment for the calibration of air pressure.
However, the applicant found that static calibration is used in the existing technology. Those barometers are provided in very limited places only, for example, they are often used in education agency or observatory. Therefore, it is not easy to use those barometers in mobile devices.
Furthermore, in case of the existing method is based on weather observation, a barometer on the clear position for altitude from the ocean surface needs to be set up. Therefore, altitude of the measurement point must be clear, otherwise correct air pressure cannot get measured for the calibration.
Therefore, another barometer is needed separately from the calibration target and the dynamic calibration of air pressure is difficult because the changing of air pressure occurs momentarily in a mobile device.